According to Nomura in the DVD commentary, the original movie was only supposed to be 20 minutes. The details of the original story is that it featured someone requesting a message to be sent to Cloud. The message is then relayed to Cloud through several children and, when the message finally reaches Cloud, it is revealed who the messenger is. Although Nomura insisted that he very much liked the original script, as it became the foundation for the theme of the final result of the movie, he decided to make the project more grand in scope because early word of this movie generated so much interest that a demand for the film to be feature length eventually became so great that Nomura complied.
After Square and Enix merged to Square Enix in 2003, the production of the film started. As there was little time, Nomura began developing a textual storyboard instead of a visual storyboard. He made a timeline of the story and wrote down all the elements of the story from the beginning to the end as keywords. The creators of the film had no prior knowledge of how to make a movie, and it was based on their knowledge of in-game movies. They used motion capture in the film's battle scenes, but the parts that were not humanly possible had to be done by hand.